Elliptical symmetry and exchangeability with characterizations

AbstractWe establish certain general characterization results on elliptically symmetric distributions and exchangeable random variables. These results yield, in particular, the results given earlier by Maxwell, Bartlett, Kingman, Ali, Smith, Arnold and Lynch, and several others

Reassembly of fractured object using fragment topology

This work presents our results on reassembly of broken objects using a newly developed fragment topology and feature extraction methodology. The reassembly of broken objects is a common problem in different domains including computeraided bone fracture reduction and reassembly of broken artefacts . The new fragment topology combines information from intact and fractured region boundaries to reduce possible correspondences between the fragments and optimise our iterative matching process. Experiments performed on different multifragment objects show that the proposed topology can be effectively applied, completing the process in a small number of iterations and with average alignment error 0.12mm

Metabolic Depression in Cunner (Tautogolabrus adspersus) Is Influenced by Ontogeny, and Enhances Thermal Tolerance

To examine the effect of ontogeny on metabolic depression in the cunner (Tautogolabrus adspersus), and to understand how ontogeny and the ability to metabolically depress influence this species' upper thermal tolerance: 1) the metabolic rate of 9°C-acclimated cunner of three size classes [0.2–0.5 g, young of the year (YOY); 3–6 g, small; and 80–120 g, large (adult)] was measured during a 2°C per day decrease in temperature; and 2) the metabolic response of the same three size classes of cunner to an acute thermal challenge [2°C h−1 from 10°C until Critical Thermal Maximum, CTMax] was examined, and compared to that of the Atlantic cod (Gadus morhua). The onset-temperature for metabolic depression in cunner increased with body size, i.e. from 5°C in YOY cunner to 7°C in adults. In contrast, the extent of metabolic depression was ∼80% (Q10 = ∼15) for YOY fish, ∼65% (Q10 = ∼8) for small fish and ∼55% (Q10 = ∼5) for adults, and this resulted in the metabolic scaling exponent (b) gradually increasing from 0.84 to 0.92 between 9°C to 1°C. All size classes of cunner had significantly (approximately 60%) lower routine metabolic rates at 10°C than Atlantic cod. However, there was no species' difference in the temperature-induced maximum metabolic rate, and this resulted in factorial metabolic scope values that were more than two-fold greater for cunner, and CTMax values that were 6–9°C higher (∼21 vs. 28°C). These results: 1) show that ontogeny influences the temperature of initiation and the extent of metabolic depression in cunner, but not O2 consumption when in a hypometabolic state; and 2) suggest that the evolution of cold-induced metabolic depression in this northern wrasse species has not resulted in a trade-off with upper thermal tolerance, but instead, an enhancement of this species' metabolic plasticity

Thermal Comfort Assessment Based on Measurement and Questionnaire Surveys in a Large Mechanically Ventilated Space

This paper presents a thermal comfort study in a large occupied office (floor-to-ceiling height >5m) ventilated by a simple mixing ventilation system. The evaluation was conducted during the summer seasons of 2016 and 2017 using three different tools; (a) long term monitoring, (b) short term detailed measurements and (c) occupant questionnaire. Long term monitoring included air temperature and relative humidity at several locations and heights within the space with external conditions retrieved form a weather station on the roof of the building. The short term spot measurements included air temperature, relative humidity and air speed each at three vertical occupancy heights and the inlet diffusers. The surveys involved collection data using questionnaires developed based on ISO 10551. Analysis of long term data using temperature clouds indicate that the building can be approximated to be free running. A comparison between the measurement (analysed using PMV/PPD and adaptive thermal comfort) and the questionnaire surveys’ results show good agreement between predictions and occupant evaluation. The existing ventilation system was able to meet the requirement for thermal comfort in this large enclosure. However, with regards to the air movement, it did not achieve the recommended levels and this has affected occupant responses

A Trinomial Difference Distribution

A trinomial difference distribution is defined and its distributional properties are illustrated. This distribution present the binomial difference distribution as a special case. The moment estimators and maximum likelihood estimators of the trinomial difference distribution are compared via simulation study. Two applications are modeled with the trinomial difference distribution and compared with other possible distributions.Una distribución de diferencia trinomial se define en este artículo así como sus propiedades distribucionales. Esta distribución cuenta con la distribución de diferencia binomial como un caso particular. Los estimadores de momentos y de máxima verosimilitud son comparados vía un estudio de simulación. Dos aplicaciones son modelados con la distribución diferencia trinomial y se comparan con otras distribuciones posibles

GROWTH AND IMMUNITY CROSS-TALK IN RAINBOW TROUT: SUPRSSION OF THE INSULIN-LIKE GROWTH FACTOR SYSTEM DURING INFECTION

International audienceDuring disease and infection it is probable that growth is attenuated , the molecular pathways involved are poorly characterised. We postulated that the insulin - like growth factor (IGF) axis - a central endocrine governor of vertebrate growth - is repressed during infection to promote resource reallocation towards immunity. T his hypothesis was tested in rainbow trout ( Oncorhynchus mykiss ) challenged by Aeromonas salmonicida (AS), a Gram - negative bacterial pathogen, or viral hemorrhagic septicemia virus (VHSv) at hatch, first feeding and 3 weeks - post first - feeding. Quantitative transcriptional profiling was performed for genes encoding IGF hormones, all salmonid IGF - I receptor and IGF binding proteins , and a panel of marker genes for growth and immune status. Many IGF axis genes were developmentally upregulated in concert with g enes controlling muscle protein synthesis, recapturing the onset of complex growth regulation. There were also differences in the developmental response of the IGF axis to AS and VHSv, with the VHSv challenge causing strong downregulation of many genes. De spite this, IGFBP - 1A1 and IGFBP - 6A2 subtypes - each negative regulators of IGF signalling - were massively induced by AS and VHSv in striking correlation with host defence genes regulated by cytokine pathways. Follow up experiments demonstrated a massive u pregulation of IGFBP - 1A1 , IGFBP - 6A2 and proinflammatory cytokine genes , associated with large downregulation of genes encoding IGF hormones and IGF - I receptor in spleen and head kidney of rainbow trout challenged by a different bacterium, Yersinia ruckeri . Based on our findings, we propose a model where certain IGFBP subtypes are directly regulated by cytokine signalling pathways, allowing immediate modulation of growth and/or immune system phenotypes according to the level of activation of immunity. Our fi ndings provide new and comprehensive insights into cross - talk between conserved pathways regulating teleost growth, development and immunit

Distinct Relationship Between Cognitive Flexibility and White Matter Integrity in Individuals at Risk of Parkinson’s Disease

Background and Objective: Executive dysfunction is the most common cognitive impairment in Parkinson’s disease (PD), occurring even in its early stages. In our study, we applied diffusion tensor imaging (DTI) to investigate white matter integrity and its association with a specific executive function such as cognitive flexibility in individuals with risk factors for PD. Methods: We examined 50 individuals with risk factors for developing PD and 24 healthy controls from the TREND (Tübinger Evaluation of Risk Factors for Early Detection of Neurodegeneration) study including neuropsychological evaluation and DTI. Cognitive flexibility was assessed using the trail making test (TMT). Tract based spatial statistics (TBSS) were employed to assess white matter abnormalities and their correlation with cognitive flexibility. Results: TMT performance correlated with mean and axial diffusivity in several white matter regions, predominantly in the frontoparietal white matter. These effects were stronger in PD risk persons (PD-RP) than in controls as evidenced by a significant group interaction. White matter integrity and TMT performance did not significantly differ across groups. Conclusion: Based on our results, PD-RP do no exhibit white matter changes or impaired cognitive flexibility. However, specific executive functions in PD-RP are more related to white matter alterations than in healthy older adults

A Bivariate Model based on Compound Negative Binomial Distribution

A new bivariate model is introduced by compounding negative binomial and geometric distributions. Distributional properties, including joint, marginal and conditional distributions are discussed. Expressions for the product moments, covariance and correlation coefficient are obtained. Some properties such as ordering, unimodality, monotonicity and self-decomposability are studied. Parameter estimators using the method of moments and maximum likelihood are derived. Applications to traffic accidents data are illustrated.Un nuevo modelo de dos variables se introduce mediante la composición distribuciones binomiales negativos y geométricos. propiedades distributivas, incluyendo distribuciones conjuntas, marginales y condicionales se discuten. se obtienen las expresiones para los momentos de productos, la covarianza y el coeficiente de correlación. Se estudian algunas propiedades tales como pedidos, unimodalidad, monotonía y la auto-decomposability. estimadores de parámetros utilizando el método de los momentos y de máxima verosimilitud se derivan. Aplicaciones a los datos de accidentes de tráfico se ilustra

Gait decline while dual-tasking is an early sign of white matter deterioration in middle-aged and older adults

Loss of white matter integrity (WMI) is associated with gait deficits in middle-aged and older adults. However, these deficits are often only apparent under cognitively demanding situations, such as walking and simultaneously performing a secondary cognitive task. Moreover, evidence suggests that declining executive functions (EF) are linked to gait decline, and their co-occurrence may point to a common underlying pathology, i.e., degeneration of shared brain regions. In this study, we applied diffusion tensor imaging (DTI) and a standardized gait assessment under single- and dual-tasking (DT) conditions (walking and subtracting) in 74 middle-aged and older adults without any significant gait or cognitive impairments to detect subtle WM alterations associated with gait decline under DT conditions. Additionally, the Trail Making Test (TMT) was used to assess EF, classify participants into three groups based on their performance, and examine a possible interaction between gait, EF, and WMI. Gait speed and subtracting speed while dual-tasking correlated significantly with the fractional anisotropy (FA) in the bilateral anterior corona radiata (highest r = 0.51/p < 0.0125 FWE-corrected). Dual-task costs (DTC) of gait speed correlated significantly with FA in widespread pathways, including the corpus callosum, bilateral anterior and superior corona radiata, as well as the left superior longitudinal fasciculus (highest r = −0.47/p < 0.0125 FWE-corrected). EF performance was associated with FA in the left anterior corona radiata (p < 0.05); however, EF did not significantly mediate the effects of WMI on DTC of gait speed. There were no significant correlations between TMT and DTC of gait and subtracting speed, respectively. Our findings indicate that gait decline under DT conditions is associated with widespread WM deterioration even in middle-aged and older adults without any significant gait or cognitive impairments